implemented tabCompletion and historyStoring features...

dash-shell.c

@@ -10,39 +10,39 @@ Basic working of Dash shell:
 #include <unistd.h>
 #include <string.h>
 #include <stdlib.h>
+#include <readline/readline.h>
+#include <readline/history.h>
+#include <sys/wait.h>
 
-char* command;
-char** argument_list;
-char* builtin_functions_name_list[] = {"help","-","cd","about"};
+char **argument_list;
+char *builtin_functions_name_list[] = {"help", "-", "cd", "about"};
 
 void exit_shell()
 {
     printf("Bye Bye");
     exit(0);
 }
+
 void about()
 {
     system("cat banner.txt");
 }
 
-void cd(char** cmd) 
+void cd(char **cmd)
 {
-    if(cmd[1] == NULL)
+    if (cmd[1] == NULL)
     {
         printf("Wrong Usage! Use cd /directory");
-        return ;
-
+        return;
     }
     else
     {
-       if(chdir(cmd[1]) != 0)
-       {
-        printf("Directory not found!");
-        return ;
-       }
-
+        if (chdir(cmd[1]) != 0)
+        {
+            printf("Directory not found!");
+            return;
+        }
     }
-
 }
 
 void help()
@@ -53,160 +53,108 @@ void help()
     printf(" about -> about the program\n");
 }
 
-void init()// set up termianl add colour as green,red.
+void init()
 {
-
     printf("\033[1;32m");
     printf("\n");
     system("cat banner.txt");
     printf("\n");
     system(" echo HELLO $USER");
 }
-int check_builtins() //returns 0 for false 1 for true
+
+int check_builtins(char *command) 
 {
     int builtin_number = -1;
-    int size = sizeof(builtin_functions_name_list)/sizeof(char *);
-    for(int i = 0; i<size; i++)
+    int size = sizeof(builtin_functions_name_list) / sizeof(char *);
+    for (int i = 0; i < size; i++)
     {
-        if(strcmp(command,builtin_functions_name_list[i]) == 0)
+        if (strcmp(command, builtin_functions_name_list[i]) == 0)
         {
-        builtin_number = i;
-        break;
+            builtin_number = i;
+            break;
         }
     }
     switch (builtin_number)
     {
-
-
     case 0:
         help();
         return 1;
-
-
     case 1:
         exit_shell();
         return 1;
-
-
     case 2:
         cd(argument_list);
         return 1;
-
-
     case 3:
         about();
         return 1;
-
-
     default:
-    return 0;
-
-    }
-}
-
-
-
-char* input()
-{
-    command = malloc(sizeof(char) * 1000);
-    int ch;
-    int n=0;
-    while (1) {
-    // Read a character
-    ch = getchar();
-
-
-    // If we hit EOF, replace it with a null character and return.
-    //getchar() returns EOF when at end. 
-    if (ch == EOF || ch == '\n') {
-      command[n] = '\0';
-      return command;
-    } 
-
-    else {
-      command[n] = ch;
+        return 0;
     }
-    n++;
-
-}
-return command;
 }
 
 #define DELIMITER " \t\r\n\a"
 
-char** parse(char* input)
+char **parse(char *input)
 {
     int position = 0;
-     char** arguments = malloc(sizeof(char*)*1000);
-    char* inputed;
-    
-    inputed = strtok(input,DELIMITER);
-    while(inputed != NULL)
+    char **arguments = malloc(sizeof(char *) * 1000);
+    char *inputed;
+
+    inputed = strtok(input, DELIMITER);
+    while (inputed != NULL)
     {
         arguments[position] = inputed;
-        //printf("%s",arguments[position]);
+        // printf("%s",arguments[position]);
         position++;
-
-        inputed = strtok(NULL , DELIMITER);
-
+        inputed = strtok(NULL, DELIMITER);
     }
     arguments[position] = NULL;
     return arguments;
-
 }
 
 int execute()
 {
-    while(1)
+    char *command;
+    while (1)
     {
-        printf("\n");
-        printf("🐚 -> ");
-
-    //printf("\033[1;32;40m");//Green \033[1;32m
-     command = input();
-     printf("\n");
-     int status;
-     argument_list = parse(command);
-     if(check_builtins())
-     {
-        printf("\n");
-     continue;
-     }
-
-    int pid = fork();
-
-    if (pid == 0) {
-
-        //printf("\n");
-        int status_code = execvp(command, argument_list);
-
-        printf("\033[5;31m ERROR! Command not found.\n"); //Adding error blinker here
-
-        if (status_code == -1) {
-            printf("\033[25;32m\n");
-            return 1;
+        command = readline("🐚 -> ");
+        if (strcmp(command, "") == 0) {
+            continue;
         }
+        add_history(command);
+        argument_list = parse(command);
+        if (check_builtins(command))
+        {
+            continue;
+        }
+        int pid = fork();
+        if (pid == 0)
+        {
+            int status_code = execvp(command, argument_list);
+            printf("\033[5;31m ERROR! Command not found.\n");
+            if (status_code == -1)
+            {
+                printf("\033[25;32m\n");
+                return 1;
+            }
+        }
+        else
+        {
+            int status;
+            do
+            {
+                int wpid = waitpid(pid, &status, WUNTRACED);
+            } while (!WIFEXITED(status) && !WIFSIGNALED(status));
+        }
+        free(command);
     }
-    else {
-        // Old Parent process. The C program will come here
-        do {
-      int wpid = waitpid(pid, &status, WUNTRACED);
-    } 
-    while (!WIFEXITED(status) && !WIFSIGNALED(status));
-
-
-    }
-    }
-
     return 0;
-
 }
- int main()
- {
-    //printf("\n");
+
+int main()
+{
     init();
     execute();
-
-
- }
-
+    return 0;
+}